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TRANSCRIPT
Contents
History of PWR
Plant Overall
Reactor Coolant System
Steam and Power Conversion System
Auxiliary System
Plant Protection System
Other systems
Main Steam SystemCondensate SystemMain Feedwater System
CWSCVCSCCWS ESWSFuel Storage and Handling SystemSpent Fuel Pool Cooling and Clean up System (SFPCCS)ESF (Engineered Safety Features)
Circulating water system To condense the steam and transfer that heat to the environment Main condenser
Steam condensation on thousands of condenser tubes No physical contact between steam and the environment In vacuum: any tube leakage will produce an inflow of water into condenser
Circulating water system
Circulating water system Takes water from the ocean/lake and discharges back into it
Expected temperature increase: 5~10C (for 1000 MW) Flow rate: ~ 50 ton/sec.
Cooling tower Forced draft cooling tower Natural convection cooling tower
Circulating water system
CVCS (Chemical and Volume Control System)
Major support system for RCS
Purify RCS using filters and demineralizers, minimize the amount of radioactive material in coolant
Add/remove boron
Maintain the level of PRZ
Volume control tank
Letdown line
Charging line
Auxiliary System
CCWS (Component Cooling Water System)
Closed loop, two independent trains
Provide coolant to components
Cooled by ESWS (Essential Service Water System)
CCW pumps
CCW heat exchanger
Tube: ESWS
Shell: CCW
Surge tank (완충탱크)
Auxiliary System
ESWS (Essential Service Water System)
Auxiliary System
ESWS (Essential Service Water System)
운전경험
해수취수구이물질,가시고기,해파리,새우떼유입에의한발전정지및원자로정지
1988고리4호기
– 가시고기떼유입으로순환수계통압력상승 원자로수동정지
1991고리4호기
– 태풍글래디스의영향으로취수구에다량의오물이유입
– 2차기기냉각해수유량상실 2차측기기온도증가 /복수기진공저하 터빈및원자로정지
2001울진1,2호기, 2006울진1,2호기
– 새우떼취수구유입 순환수펌프정지 복수기진공저하 주급수펌프정지 원자로정지
2014월성 3호기
– 월성3호기계획예방정비중취수구잠수작업자인명사고발생
Auxiliary System
Fuel Storage and Handling System Nuclear fuel
Contains fissile material and, after irradiation, highly radioactive fission and activation products.
The most significant design features
Provide the necessary assurances that the fuel and core components can be received, handled, stored and retrieved without undue risk to health, safety or the environment.
Maintaining subcriticality of the fuel
Ensuring the integrity of the fuel
Cooling irradiated fuel
Ensuring radiation protection and safety
in accordance with the Basic Safety Standards
Preventing unacceptable releases of
radioactive material to the environment.
Auxiliary System
Fuel Storage and Handling System
Auxiliary System
Fuel Storage and Handling System Layout
Auxiliary System
Fuel Storage and Handling System
Auxiliary System
Fuel Storage and Handling System
Auxiliary System
Fuel Storage and Handling System Fresh fuel (new fuel)
Fuel storage racks/ New fuel elevator
Dry storage
Auxiliary System
Fuel Storage and Handling System Spent fuel pools
Located inside the plant’s protected area. Contain an enormous quantity of water, which acts to cool the fuel and provide radiation shielding. Have no drains that would allow the water to drain out. Can be filled using a variety of water
sources, if needed. Have large safety margins, including about 20 feet of water above the top of the fuel Are robust, with very thick, steel‐reinforced concrete walls and stainless‐steel liners. May be located below ground level, shielded by other structures, or surrounded by walls that would
protect the pool from a plane crash or other impact.
Auxiliary System
Contents
History of PWR
Plant Overall
Reactor Coolant System
Steam and Power Conversion System
Auxiliary System
Plant Protection System
Other systems
Main Steam SystemCondensate SystemMain Feedwater System
CWSCVCSCCWS ESWSFuel Storage and Handling SystemSpent Fuel Pool Cooling and Clean up System (SFPCCS)ESF (Engineered Safety Features)
ESF (Engineered Safety Features) Functions
To localize, control, mitigate and terminate accidents To hold exposure levels below the limits
Containment system The containment structure which forms a virtually leak tight barrier to the escape of fission product
Containment spray system To reduce containment pressure and remove iodine from the containment atmosphere after a
primary or secondary pipe break inside containment.
Safety injection system To provide borated water to cool the reactor core in the event of an accidental depressurization The combination of control rods and the boron in the injection water provides the necessary
negative reactivity to maintain the reactor shutdown.
Shutdown cooling system To maintain the RCS at refueling temperature for extended period.
Auxiliary feedwater system To provide emergence heat removal capability upon loss of normal feedwater.
Safety depressurization system To provide a manual means of rapidly depressurizing the RCS
Engineered Safety Features
• Reactor shut down• Remove decay heat• Minimize the radioactivity release
ESF (Engineered Safety Features) Containment system
Design pressure: ~ 4 bar Internal diameter: ~ 44 m, thickness: ~ 1.2 m Dome radius: ~ 21.9 m Height: ~ 66 m
Engineered Safety Features
ESF (Engineered Safety Features) SIS (Safety Injection System)/ ECCS (Emergency Core Cooling System)
Engineered Safety Features
Safety Injection Systems
ESF (Engineered Safety Features) SIS (Safety Injection System)/ ECCS (Emergency Core Cooling System)
Engineered Safety Features
ESF (Engineered Safety Features) SIS (Safety Injection System)
OPR1000: HPSI, SIT, LPSI APR1400: HPSI, SIT
High pressure safety injection pump 1 pump: connected to 4 cold legs & 1 hot leg
Safety injection tank 1 tank: connect to 1 cold leg D=2.74 m H=13.6 m
Low pressure safety injection pump 1 pump: connected to 2 cold legs
Engineered Safety Features
ESF (Engineered Safety Features) SIS (Safety Injection System)/ ECCS (Emergency Core Cooling System)
OPR1000: HPSI, SIT, LPSI APR1400: HPSI, SIT
Engineered Safety Features
SteamGenerator Steam
Generator
Control RodDriving Mechanism
Reactor Vessell
Lower Plenum
Downcomer
Reactor Coolant Pump
Cold Leg (*4)
Hot Leg (*2)
ReactorCore
Safety Injection Nozzles (*4)(Cold Leg Injection Mode)
Safety Injection Nozzles (*4)(Direct Vessel Injection Mode)
정상 운전 시 냉각재 경로
ESF (Engineered Safety Features) SIS (Safety Injection System)/ ECCS (Emergency Core Cooling System)
OPR1000: HPSI, SIT, LPSI APR1400: HPSI, SIT Simplified SIS 4 mechanical trains with 2 electrical trains
Engineered Safety Features
ESF (Engineered Safety Features) OPR1000 vs. APR1400
Engineered Safety Features
ESF (Engineered Safety Features) SCS (Shutdown Cooling System)/ RHRS (Residual Heat Removal System)
Engineered Safety Features
ESF (Engineered Safety Features) SCS (Shutdown Cooling System)/ RHRS (Residual Heat Removal System)
To continue the cooldown by removing heat from the core and transferring it to the environment.
Engineered Safety Features
ESF (Engineered Safety Features) Auxiliary feedwater system
To provide emergence heat removal capability upon loss of normal feedwater.
Engineered Safety Features
ESF (Engineered Safety Features) Auxiliary feedwater system
To provide emergence heat removal capability upon loss of normal feedwater. Replaced by PAFS in APR+
Engineered Safety Features
PPS (Plant Protection System) RPS(Reactor Protection System)
To provide an emergency shutdown of the reactor to protect the core and the reactor coolant system pressure boundary
ESFAS(Engineered Safety Features Actuation System) To provide those functions required to prevent the release of significant amounts of radioactive
material to the environment in the event of pressure boundary rupture.
The PPS continuously monitors selected safety‐related parameters Such as neutron flux, pressurizer pressure, steam generator pressure and level
The PPS automatically initiates plant protective action in the form of initiation of the appropriate function whenever a monitored plant parameter reaches a predetermined level. RPS trip and/or ESF actuation
Plant Protection System
PPS (Plant Protection System) Monitored parameters
Core power (neutron flux and core inlet/outlet temperatures) Reactor coolant system pressure Departure from nucleate boiling ratio (DNBR) in the limiting coolant channel of the core Peak local power density in the limiting fuel pin of the core Steam generator water level Steam generator pressure Containment pressure Refueling water tank water level Reactor coolant system flow
– Reactor coolant pump speed and steam generator primary differential pressure
Plant Protection System
PPS (Plant Protection System) Trip functions
Variable Overpower– To limit the plant's maximum steady state power level, in conjunction with the DNBR/LPD trips.
High Logarithmic Power Level– To ensure the integrity of the fuel cladding and coolant system boundary in the event of unplanned
criticality from a shutdown condition, resulting from either dilution of soluble boron or withdrawal of CEAs.
High Local Power Density– To prevent the linear heat rate (㎾/ft or w/㎝) in the limiting fuel pin in the core from exceeding the fuel
design limit in the event of defined anticipated operational occurrences.
Low Departure From Nucleate Boiling Ratio (DNBR)– To prevent the DNBR in the limiting coolant channel in the core from exceeding the fuel design limit in the
event of defined Anticipated Operational Occurrences.
High Pressurizer Pressure– To help assure the integrity of the Reactor Coolant Pressure Boundary for design basis events
Low Pressurizer Pressure– To assist the Engineered Safety Features System in the event of a coolant accident and to provide a reactor
trip in the event of reduction in pressurizer pressure.
Low Steam Generator Water Level
– To assist the Engineered Safety Features System by assuring that there is sufficient time for actuating the auxiliary feedwater pumps to remove decay heat from the reactor in the event of a reduction of steam generator water inventory.
Plant Protection System
PPS (Plant Protection System) Trip functions
High Steam Generator Water level– To provide protection in conjunction with the MSIS to protect Main Steam System components from being
damaged by excessive moisture carryover from the steam generators.
Low Steam Generator Pressure– To provide protection against excess secondary heat removal events
High Containment Pressure– To assist the Engineered Safety Features System by tripping the reactor coincident with an event which
results in significant mass and energy releases into the containment.
Low Reactor Coolant Flow– To limit the consequences of a sheared reactor coolant pump shaft and steam line break.
Manual Trip
Plant Protection System
PPS (Plant Protection System) ESFAS Functions
Safety Injection Actuation Signal (SIAS) Containment Isolation Actuation Signal (CIAS) Containment Spray Actuation Signal (CSAS) Recirculation Actuation Signal (RAS) Main Steam Isolation Signal (MSIS) Auxiliary Feedwater Actuation Signal (AFAS)
Plant Protection System
Plant Monitoring System Core operating Limit Supervisory System In‐core Instrumentation System Ex‐core Neutron Flux Monitoring System Inadequate Core Cooling Monitoring NSSS Integrity Monitoring System Radiation Monitoring System Containment Vessel Monitoring System Post Accident Monitoring System Bypass and Inoperable Status Indications
Other Systems
Plant Control System Reactor Regulating System Control Element Drive Mechanism Control System Main Feedwater Contorl System Steam Bypass Control System Reactor Power Cutback System Pressurizer Pressure Control System Pressurizer Level Control System
Other Systems
Radioactive Waste Management System Gaseous Radioactive Waste System Liquid Radioactive Waste System Solid Radioactive Waste System
Compressed Air System Chilled Water System
Other Systems
